The present invention generally relates to fluid accumulators and more particularly relates to a hydraulic fluid accumulator for brake systems.
A hydraulic fluid accumulator of this type is generally disclosed in DE-OS 29 10 554. The first media separation element in the prior art hydraulic fluid accumulator is configured as a metal pleated bellows, while the second media separation element is provided by an elastic partition.
It is disadvantageous in the prior art hydraulic fluid accumulator that an effective separation of media cannot be achieved. Tests have shown that leakage at the pleated bellows that is usually absolutely gas-tight allows the gas to propagate from the first chamber into the second chamber, from there diffusing through the material of the elastic partition into the third chamber. This causes a massive entry of gas into the hydraulic system
Therefore, an object of the present invention is to improve upon a hydraulic fluid accumulator of the type mentioned hereinabove so that the entry of gas into the following hydraulic system is prevented, thereby ensuring a significant increase in the reliability in operation.
According to the present invention, this object is achieved in that the second media separation element is formed of a metal piston delimiting a chamber that is adapted to be vented.
Extremely compact constructions of the subject matter of the present invention are achieved in that the piston is sealed and guided in the housing and embraces the first media separation element in a radial direction and, respectively, that the first chamber is designed between the wall of the housing and the first media separation element and that both the second and the third chamber is provided within the first media separation element.